The central goal of the proposed research is to improve the long-term transmission of multiple channels of information from a cochlear implant to the brain. We also exploit the cochlear implant as a research tool to gain understanding of brain mechanisms of normal hearing. We will monitor central nervous system responses to cochlear implant stimulation at the level of the auditory cortex. Previously, investigators have described the cortical activation patterns arising from cochlear implant stimulation immediately post-implant; however, the cortical activation patterns are likely to vary with time due to activity and adaptation throughout the neural system. In these proposed studies we aim to record the cochlear implant-evoked activity within the auditory cortex over the course of approximately 30 days. These studies involve cochlear implant stimulation and chronic recordings from the auditory cortex of guinea pigs.